Hyperloop: Shaping the future of transport. Part 2

With rapid population growth and increased demand for resources being two of the major challenges the construction industry is currently facing, PlanBEE student Will Marshall takes a look at how Hyperloop could potentially revolutionise the way we live, work and travel. In part two, he looks at what’s being developed and the challenges those developers face.

Hyperloop One global challenge

In May 2016, Virgin Hyperloop One commenced a global challenge that encouraged proposals for potential Hyperloop routes around the world. From over 2,600 registered teams, this number was narrowed down to just 35 semi-finalists. After much debate and assessment, 10 winners were selected. The winning teams proposed their routes in a number of countries including Canada, India, Mexico, the US and the UK.

The two proposed UK winning routes were Glasgow–Liverpool and Edinburgh–London. The former will travel via Edinburgh, Newcastle upon Tyne, Leeds and Manchester before arriving at Liverpool, at a total of 47 minutes from Glasgow. Northern Arc is the team set out to develop the project. The University of Edinburgh Hyperloop Team (HYPED) developed the latter. It will pass through Manchester and Birmingham on its way to London, travelling 666 km in 50 minutes. AECOM has also proposed a third route, which will take passengers from Scotland to Wales. It will begin in Glasgow, head east to Edinburgh, then down along the east coast to London, and finally west to Cardiff; that is 1060 km in 89 minutes.

SpaceX competition

In 2015, SpaceX announced it was hosting an annual global Hyperloop pod competition aimed to inspire innovation from the next generation of engineers and encourage students and non-students from around the world to design and develop their very own self-functioning, high-speed pod prototypes. The series of competitions take place at the SpaceX headquarters in Hawthorne, California, where they provide the required services to interested parties, including the Hyperloop tube with a six-foot outer diameter and an approximate length of one mile. Successful candidates are those whose pods reach the maximum speed while successfully decelerating before coming to a stop within 100 feet of the end of the tube. The first three competitions were arranged in January 2017, August 2017, and July 2018.

HYPED was one of the teams that competed in July 2018. With their model, known as Poddy the Second, HYPED finished sixth. Poddy the Second was unveiled at Ryder Architecture’s Cooper’s Studios, Newcastle upon Tyne, in July 2018 as part of the Great Exhibition of the North (GEON). Ryder and HYPED also received a visit from Prince William, Duke of Cambridge who came to view Ryder’s Horse to Hyperloop exhibition.

Challenges

Of course, as with any new technology, especially one as large, as complex and as controversial as Hyperloop, there are challenges that face the teams involved to ensure that the potential benefits of it are realised. Hyperloop has received intense criticism and scrutiny since its proposal, with the primary concerns involving safety, economic and environmental issues.

Safety questions

When you think of the idea of propelling through a long vacuum tube at speeds of up to 1080 km/h (670 mph), several questions around safety are automatically raised. One key concern is how the system will cope with emergencies such as air leaks, rapid depressurisation and natural disasters. Risk assessment includes not only what could happen, but also what emergency procedures will be in place. The following are some of the most widely discussed issues.

Passenger emergency and evacuation

Any serious accident may result in the loss of oxygen to onboard passengers. In that event, oxygen masks would deploy, similar to what happens on aeroplanes. The pod then completes its journey in the safest manner as to not make situations worse. Sensors along the tube and on the pod communicate with each other and instantly let control centres and emergency services know of any air leaks and other issues. Travellers will also be able to communicate instantly with control centres and emergency services, and aircraft-like procedures will be used to address passenger emergencies

According to SpaceX, Hyperloop’s short travel times show that the best course of action in an emergency would be to complete the journey in a few minutes where emergency services would be waiting at the destination. However, should a more serious incident occur, an evacuation may be required. This is instantly more complex as it would require escape hatches, which could be prone to air leaks. It is still unclear exactly how this will be addressed.

Tube puncture

Air pressure on Earth is around 10 tonnes per square metre at sea level. Since the Hyperloop tube has a significantly lower air pressure inside than that of the outside atmosphere, it experiences extremely intense forces from all directions. Hyperloop companies have addressed this issue by constructing high-strength steel tubes made to withstand changes in air pressure. The tubes are also designed to be incredibly difficult to penetrate from any external projectile or event. Having said that, questions have been raised regarding the effects that a physical puncture will have should it happen. Air will immediately start to enter the tube at a rapid rate. The tubes will have to be extremely strong in order to withstand this instant pressure change without tearing apart like paper. To combat this, the tubes are designed to safely withstand leaks and holes while maintaining their structural integrity and can withstand an internal air pressure of 100 Pa.

For comparison, the pressure of the atmosphere at sea level (1 Atmosphere) is over 101,000 Pa. Many claim if a puncture in the tube occurs, the sheer amount of air rushing into the tube at such a speed and force would cause explosive decompression, destroying the entire tube and ripping it apart like paper. This is a significant challenge for Hyperloop engineers to overcome. They need to design a tube strong enough to withstand intense forces and maintain structural integrity should the tube be breached. Hyperloop engineers claim that a sudden inflow of air into the tubes would theoretically just slow down the pods, which are designed to withstand pressure changes. Sensors along the route will communicate issues to the system’s control centre, which will be able to section off areas of the route to re-pressurise them and undertake maintenance.

Pod depressurisation

At the top of the concerns list is pod depressurisation, which could potentially be deadly in some circumstances. The conditions of the partial vacuum in the tube resemble the conditions of space more than the conditions outside of an aircraft at 37,000 feet. The air pressure in the tube, according to Virgin Hyperloop One, is equivalent to the air pressure at an altitude of 200,000 feet above sea level. That sort of air pressure could initiate severe hypoxia and traumas and could prove fatal to anyone exposed to it for a significant amount of time. Unless safety features could re-pressurise the cabin quickly enough, the results could be devastating. However, with the system so close to the ground, re-pressurisation should be straightforward. Minor leaks should be manageable by deploying the reserve air, which would maintain internal pressure long enough to reach the destination safely.

Poddy the Second as unveiled at Ryder Architecture’s Cooper’s Studios in Newcastle upon Tyne – Image courtesy of HYPED.

Environmental hazards

Earthquakes

Musk’s initial proposal of a potential Hyperloop route was from Los Angeles to San Francisco up central California. California is known to be a seismically active region. Therefore, Hyperloop will be required to withstand significant ground shifts while maintaining its structural integrity. Hyperloop teams state that the tubes will be atop pylons designed to absorb the forces during an earthquake, using similar technology to many earthquake-proof buildings today. Additionally, pods will activate their emergency braking system during earthquake periods to ensure the safety of the passengers.

Thermal expansion

Most people know that when materials, particularly metals, get hot they expand. The Eiffel Tower can become 17 cm taller in the summer than in the winter due to the increase in temperature. This is perfectly manageable in most cases through expansion joints that allow construction materials to expand and contract during these periods. However, these expansion joints have gaps for the materials to expand into, which means this system couldn’t be used for Hyperloop because they are not airtight. Despite steel having a relatively low thermal expansion rate, extreme effects of thermal expansion can be seen when the tube extends hundreds of miles long. Furthermore, a long steel tube exposed to the California heat will not heat evenly. The top of the tube will experience more expansion than the underside because it receives more sunlight. For a 600 km (372 miles) tube, a temperature difference of just 3°C between the top and underside of the tube could cause the top to expand around 25 m more than the underside. This is in addition to the hundreds of meters of linear expansion the entire tube will already experience. There are ways to combat this, but they aren’t easy. Hyperloop engineers have stated that they would use telescoping tubes, similar to those used to access aeroplanes, at either end of the tube.

Expansion joints could be used, similarly to those found on pipes in enclosed areas where alternative methods such as loops and offsets are difficult to implement. That involves having an external pipe that allows the two other pipes to move freely within it. The external pipe maintains the seal, but many argue that having these would just create more areas of potential failure.

Political and economic challenges

Costs

According to Musk’s Alpha white paper, Hyperloop will be considerably cheaper to construct and run than high speed rail and other conventional rail travel. In Britain, HS2 has been very controversial. It initially planned to start transporting passengers by the end of 2026 but has since been pushed back to 2033. It aims to transport passengers from Birmingham to London and vice versa between 30 and 49 minutes each way. However, Hyperloop claims to be able to take passengers between Edinburgh and London in only one minute longer than the HS2 route and at a significantly lower cost.

It is difficult to say exactly how a Hyperloop project would develop in Britain, but HS2 may offer an indication, and it doesn’t look good for the innovative transport method. HS2 has had many issues from the beginning, with the main issue apparently being cost. In 2013, HS2 raised its price from £32.7 billion to “a maximum,” £42.6 billion. This “maximum” has now risen to £56 billion and is likely to rise again in the future.

Many have disregarded Musk’s estimate of around US$6 billion for a system between Los Angeles and San Francisco as dubious, with some believing it could perhaps be closer to US$100 billion. However, even if the costs were that high (which is also slightly doubtful) when comparing it to the US$68 billion California High Speed Rail, it could be argued that the additional costs are warranted given the significantly faster speeds and lower commute times. However, this would depend on a number of other factors including the number of passengers it is likely to transport per annum.

Land acquisition

With HS2, land acquisition is another controversial obstacle the project has encountered since its proposal. The construction of a high-speed rail line will result in the demolition of homes and cause damage and disruption to rural areas of England. Huge amounts of land have to be flattened to be built upon. Initial figures showed that 250 acres of green belt land will be built upon and 600 homes will be bulldozed. The line has since been tweaked by HS2 Ltd and stated that around 18% of the London–Birmingham route will be enclosed within a tunnel.

This is perhaps where Hyperloop could prevail, with the construction of smaller, cheaper, tunnels and pylons raising the tube off the ground. Pylons holding up the tube would reduce the amount of land required and enable the system to be built on irregular terrain. However, this would have to be managed carefully to avoid sharp turns and bends, which would cause excessive G-forces that would render the system un-rideable.

The information outlined above only scratches the surface of Hyperloop. Many questions still need to be answered and obstacles addressed before we even begin to see it implemented into reality. The Middle East and other areas in Asia seem more likely to receive the first Hyperloop systems, which means that the UK, and perhaps even the US, will have to sit back and observe how it copes before even considering the prospect. It remains to be seen whether Hyperloop is a genuine contender for a fifth mode of transport, or if it’s simply still just a pipe dream…

With rapid population growth and increased demand for resources being two of the major challenges the construction industry is currently facing, PlanBEE student Will Marshall takes a look at how Hyperloop could potentially revolutionise the way we live, work and travel. In part one, he looks at the history behind the concept and the benefits of adopting it.